Reciprocating core drill



Patented June 24, 1930 UNITED STATES F'FICE LEONARD S. COT'ELIN, F COMPTON, CALIFORNIA REGIPROCATING- CORE DRILL Application filed November 29, 1926. Serial No. 151,399.

My invention relates to core drills of the time so mounted that the rotative movement of the outer barrel is not imparted to the inner barrel.

The principal object of my invention is to provide a core drill of the type described which is so constructed that the core, while being formed is protected against undue 'arring action and strain which would other- I wise have a tendency to injure the core.

Another object of my invention is to provide a core drill of the class described having its parts so arranged that the fluid between thebarrelsis prevented from jetting against the core but directed outwardly over the outer cutting teeth, thereby assisting in cleaning the cuttings and other accumulations from the teeth.

Other advantages and objects will appear -to those skilled in the art from the follow- 'f in description and drawings.

eferring to the drawings, which are for illustrative purposes only,

Fig. 1 is a vertical sectional view of al relief valve 31, such valve being arranged drill embodying a formof my' invention.

Fig. 2 is, an enlarged sectional plan view, 4 taken on the line 2-2 of Fig. 1.

' Fig. 3 is an enlarged inverted plan view of the lower or cutting end of the drill.

My core drill in the form shown consists of an outer barrel 11 threaded to a body member 12, such body member terminating at its upp'erend in a threaded pin 13 suitable for connection to an ordinary strin of cable tools, the drill and cable tools not shown) being suspended in the hole by means of the ordinary cable, (not shown).

The lower end of the outer barrel 11 is provided with a circular cutting member -or shoe 15, which is interiorly shouldered as indicated at 16 for purposes hereinafter described, such cutting member 15 also being provided with a centralv opening 17, in the face of which are disposed a series of vertically extending grooves 18 to permit of movement of fluid or mud between the inner and outer barrels of the drill.

Freely rotatable in the outer barrel 12 is an inner barrel 20, terminating at its lower end in a circular cutter 21 threaded thereto, a core catcher consisting of a ring 22 having -fingers 23 mounted thereon being supported betweenthe lower end of the barrel 20 and a shoulder 24 formed on the face of the cutter 21. The inner cutter 21 is formed with a series of teeth indicated at 25 and the outer cutting member 15 is formed with a' series of radially extending teeth 26, the teeth 26 having radially extending passages 27 therebetween to permit free movement of cuttings and fluidv or mud under the cutting member 15. It is to be understood however, that the teeth of the respective inner andouter cutters may be varied in form without departing from the spirit and scope of my invention.

The upper end of the inner barrel 20 is provided with a head 28 threaded thereto, the head being of larger diameter than the inner barrel and,being provided with a series of vertically extending passages 29 for the purposes hereinafter referred to. The head 28 is provided with a vertically extending central passage 30 fitted with a to permit fluid or other material in the inner barrel above the core to pass upwardly therethrough during the coring operation, such valve being closed at the end of the coring operation, also assisting in creating a vacuum above the core should the core start to slide out of the core barrel, thereby assisting to retain the core in the barrel during the operation of removing the drill from the hole. The head 28 is also provided with a nipple 32 extending upwardly therefrom, such nipple extending through a central opening or passage 33 in a plug 34: and engaging when in its upper'position with a ball bearing organization 35 elastically held downwardly by means of a coil spring 36 mounted in a chamber 37, in the body member 12, the fluid or mud in the core barrel heretofore referred to being permitted to pass upwardly through the valve 31, the nipple 32 and out through passages 38 and 39 in the head 12.

The drill is operated in the following manner: The drill supported on the lower end of the cable as heretofore described is alternately raised and dropped in the well, being dropped to allow the cutting shoe to strike a blow on the formation and having a spinning or rotative movement imparted thereto by the twist in the cable.

The inner barrel or core tube, being free to move in the outer barrel, engages the formation before the outer cutter strikes the same and as the outer barrel moves downwardly over the inner barrel, the nipple 32 engages bearing 35 and is yieldingly pressed downward, so that the cutter on the inner barrel is yieldingly held against the formation, as the outer cutter strikes the formation, further movement of the outer barrel causes the plug 34 to strike the head 28, thereby imparting a blow to the inner barrel.

During this movement just described, it will be noted that the nipple 32 enters the opening or passage 33 in the plug 34 and shuts oil passage of the mud from between the two barrels upward. The downward movement of the outer barrel displacing the mud above the head 28 through the grooves or slots 29 in the head causing the mud to be forcibly expelled through the slots 18 in the shoe outwardly therefrom, around the .teeth on the shoe 15, the core being protected above the core passing out of the core barrel.

through valve 31.

lVhile I have shown and described the preferred form of my invention, it is to be understood that those skilled in the art may modify the construction shown without departing from the spirit of my invention.

I claim as my invention:

1. A reciprocating core drill comprising: an outer barrel; an inner barrel freely movable therein and spaced apart from the outer barrel; cutters on the lower end of each barrel; means for yieldingly holding the inner barrel on the formation during the cutting operation, and means for forcing a quantity of the mud from between the barrels outwardly, under the cutters on the outer barrel, just prior to the engagement of the cutters on the outer barrel with the formation.

. 2. A reciprocating core drill comprising a body member having mud passage therethrough; an outer barrel mounted on said body member, an inner barrel freely mounted in said outer barrel and spaced apart from the outer barrel, cutters on the lower ends of each barrel, and means on the inner barrel adapted to enter the mud passage in said body member during a portion of the stroke to prevent the passage of mud from between the barrels through the mud passage in said body member.

3. A reciprocating core drill comprising a body member adapted to be attached to a cable, a chamber in said body member communicating with mud passages thereinabove, resilient means in said chamber, a closed outer barrel on said body member, an inner barrel freely mounted in said outer barrel spaced apart therefrom, cutters on the lower end of both barrels, and means on said inner barrel arranged to move upwardly into said chamber and engage said resilient means therein. 1

4. A reciprocating core drill comprising a body member adapted to be attached to a cable, a chamber in said body member cotnmunicating with mud passages therein, res1lient means in said chamber, a plug for said chamber having a passage therein,-an outer barrel on said body member, an inner barrel freely mounted in said outer barrel spaced apart therefrom, cutters on the lower end of both barrels,a head on the inner barrel having a passage therethrough, a valve in said passage, and a hollow nipple on said head adapted to enter and close'thepassage 11; said plug and engage the resilient means in said chamber.

In testimony whereof, I have hereunto set my hand at Los '-Angeles,' California, this 22nd day of November, 1926.

LEONARD S. COPELIN. 

